All detection methods have their minimal detection limits, inclusive metal detection. The factor which restricts the most is your product. On the second place there is the type of metal. You wish to reject all the metal, but unfortunately, this is impossible.
To avoid disappointments, it’s essential to take this aspect into account, before investing in a metal detector. It may be, that other methods or a combination with other methods are more advantageous. Or you have to adapt your process first.
The size of the rejected bodies determines the security of your product. How to obtain the right body size? By doing a research on the best practices in your branch for your type of product, you can obtain them.
The best is to consult several sources to get the ideal situation. The metal detection suppliers are a good source of information. However, you need also to carry out your own research.
By means of questionnaires, customer audits and specifications this information will get to your customers. You should avoid, that your customers leave toward your competitors, because of a lack of confidence (which is perhaps unjustified) in your product.